Device for degassing and purifying hydraulic liquid of a hydraulic power system



G. CAROL] DEVICE FOR DEGASSING AND PURIFYING HYDRAULIC Nov. 8, 1960 LQUID OF' A HYDRAULIC POWER SYSTEM Filed Augn 14, 1957 United States Patent-O DEVICE FOR DEGASSING AND PURIFYING HY- DRAULIC LIQUID OF A HYDRAULIC POWER SYSTEM Gerhard Caroli, Stuttgart, Germany, assignor to Sddeutsche Khlerfabrik Julius Fr. Behr, Stuttgart-Feuerbach, Germany Filed Allg. 14, 1957, Sel'. N0. 678,128 Claims priority, application Germany Aug. 16, 1956 y 7 Claims. (Cl. 60-52) This invention relates to hydraulic systems'and more particularly to a device for degassing and purifying hydraulic liquid contained in hydraulic systems such as hydraulic power plants and motors. I

The invention is particularly applicable to the degassing and purifying of pressure oil used in hydraulic cooling motors and the like.

It is an object of this invention to provide a device for centrifugal force caused by the swirling motion and the slow rising of the liquid causes the gas bubbles in the liquid to rise to the surface and in this way facilitates the degassing of the liquid.

Further objects and details of the invention will be apparent from the following description and the accomi panying drawings illustrated-by way of examplean embodiment of the invention. In the drawings:

Fig. 1 is a diagrammatic illustrationof vthe elements of a hydraulic power plant; 4

Fig. 2 is a vertical cross section through the center of the hydraulic liquid container of the plant; and

Fig. 3 is a horizontal section through the upper chamber of the hydraulic liquid container corresponding .to Fig. 2.

Referring now to the drawings, the power plant according to Fig. 1 comprises a pump 1 and a hydraulic motor 3 charged with hydraulic liquid, for example, pressure oil, by the pump 1 through a high pressure line or duct 2. The flow direction is indicated by the arrows. From the motor 3, the hydraulic liquid, which in most instances will be an oil, flows through a return pipe 4 into a cylindrical, hydraulic liquid container 5 and from the latter through a suction pipe 6 back to the pump 1. The cycle is thus completed.

The construction of the container 5 can be seen in detail in Figs. 2 and 3. As is shown in Fig. 2, the container 5 is divided by partition means into an upper chamber 12 and a lower chamber 13. The two chambers 12 and 13 communicate with each other through an overow pipe 11. The inlet end of this overflow pipe is located in the upper chamber 12 just below the closed front wall of the chamber 12, while the lower or outlet end 11 of the overflow pipe terminates above the inlet end of the suction line 6. The outlet 11 of the overow pipe 11 is provided with a nozzle 8. The outlet 11' and the inlet of the suction line 6 are rigidly connected with each other by means of strap or bridging members 7. An inlet pipe 14 which is screwedly connected with the return line 4, opens tangentially into the 2,959,008 Patented Nov. 8, 1960 2 lower half of the upper chamber 12. A magnetic lter 10 is arranged in the upper chamber 12. In the lower chamber 13 of the hydraulic liquid container '5 there is provided an overilow valve 15 and, further, a control valve 15', below Ithe overflow valve, as well asexit or vent means in the form of tube 9.

The hydraulic liquid which is returned from the motoi '3 through the return pipe 4 with a certain excess pressure ,enters the upper chamber 12 of the container Satangentially through the inlet pipe 14. The hydraulic liquid is in this manner imparted with a swirling motion and circulates around the permanent magnetic iilter 10 and the overflow pipe 11. Both the magnetic'lilter 10 and the overflow pipe 11 are arranged in parallel relationship relative to the cylindrical axis of the container 5 and in the vicinity thereof. The hydraulic liquid or pressure medium, after it has risen in the upper filter chamber 12, flows through the overflow pipe 11 into the lower chamber 13 which latter chamber,fin contrast to the filter chamber 12, is not entirely filled with the pres- Sure medium or hydraulic liquid. The outlet v11 of the overflow pipe 1l terminates below the liquid level of the hydraulic liquid. The pressure medium liows then under excess pressure through the nozzle 8 provided at the outlet end 11 of the pipe 11 into the funnel-shaped enlarged inlet end of the suction line 6. In doing so, the air included or contained in the hydraulic liquid or pressure medium escapes upwardly and collects in the upper portion of the chamber 13 and thus may escape through the vent or discharge tube 9.

As will be readily gathered from the above description, the invention is particularly directed to hydraulic power plants or systems, wherein a hydraulic liquid or oil contaner is interposed in the line between the hydraulic motor and the pump. Important features of the invention reside therein that the line leading from the motor Vtothe container opens up tangentially into lthe container, that the hydraulic liquid is discharged below the-inlet end' of an overflow pipe arranged within the container and conveying the hydraulic liquid, and further, that this overow pipe is arrangedV parallel to and in the vicinity of the cylinder axis of the container. By arranging the various elements in this manner, a swirling motion is imparted to the hydraulic liquid within the container, while the hydraulic liquid rises therewithin. In this manner, the liquid, upon entering the container is rapidly degassed, whereby the entire line system is liberated from air. Further, during operation, dueto the favorable pressure conditions prevailingduring this swirling movement, air which lmay be cornprised in the liquid may escape therefrom and rise upwardly whereafter this air is separated from the hydraulic cycle through exit means. In this manner one is assured that the liquid will be entirely degassed while the hydraulic liquid pump will operate quietly without being aifected by the degassing procedure.

As has been explained in conjunction with thedrawings, in accordance with a preferred embodiment of this invention, a magnetic filter is arranged within the c011- tainer. Such magnetic filter may advantageously also be used in containers in which no swirling movement of the hydraulic liquid takes place. However, particularly advantageous is the use of such magnetic filter in containers wherein the pressure medium or hydraulic liquid ows through the container in a swirling movement, since due to this swirling movement, the pressure medium is for a relatively longer period under the action of the magnet and thus, the magnetic filter can readily be arranged in the container ,in such a manner that all the hydraulic liquid which passes through the container will `at ,least once ow past the immediate vicinity of the lilter 3 surface. Consequently, an ecient filter action is obtained.

As has been explained in connection with thedrawings, the container, according to a preferred embodiment is divided into two chambers. The return line from the motor opens up tangentialily into the upper chamber of the container. From the upper chamber the liquid is conducted into the lower chamber through an overow pipe. The lower chamber is not entirely iilled with the pressure medium. The overow pipe terminates below the level of the vhydraulic liquid in the lower chamber and above the inlet end of the suction line. The outlet of the overow pipe is nozzle-shaped. In this manner pressure conditions are created in the hydraulic Aliquid cycle which favorably influence the output of the hydraulic pump and which kfacilitate and accelerate the degassing of the pressure medium or hydraulic liquid.

It will be apparent to those skilled in the art that many modifications and alterations of the device herein described and illustrated may be made without departure from the essence and spirit of the invention which for this reason shall not be limited but by the scope of the appended claims.

I claim:

1. In a hydraulic system including a iuid motor having an inlet and a discharge, pump means including a pressure line arranged to discharge uid to said motor inlet and a suction line for said pump connected to said motor discharge, the improvement comprising a degassing device in said suction line, comprising a liquid container including an upper portion having means for maintaining said portion completely lled with liquid and a lower portion having means for maintaining it tilled with liquid to a predetermined level, a first portion of said suction line returning from said uid moto-r extending into said container adjacent the bottom of said upper portion, a conduit extending between said upper portion and lower portion of said container, said conduit including an upper opening adjacent the top of said upper portion of said container and a lower opening of reduced dimension submerged in the liquld in the lower portion of said container, and a second portion of said suction line including an opening in the liquid of said container lower portion and in alignment with but spaced in an axial direction from the discharge of said conduit lower opening in the direction of discharge tiow and extending back to said pump means whereby liquid returning through said suction line to said pump is directed into the upper portion of said container and downwardly through said conduit and into the liquid of said lower container, the turbulence causing gases to be separated therefrom in said lower container and to rise to the surface of the liquid in said container,

2. In a hydraulic system according to claim l, including a vent at the upper end of the lower portion of said container.

3. In a hydraulic system according to claim 1, wherein said rst portion of said suction line is connected tangentially into the` upper portion of said container.

4. In ahydraulic 'system according to claim 1, including bridging means extending between said conduit and said second portion of said suction line.

5. In a hydraulic system according to claim 1, including uid tap meansfor discharging water from the lower portion of said container above a predetermined level.

6. In a hydraulic system according to claim l, including magnetic filter means in the upper portion of said container.

7. A liquid degassing device for positioning in the return line between a hydraulic motor and a hydraulic pump wherein liquid is forced from the motor to the pump, comprising, a Iliquid container including an upper portion and a lower portion, means for maintaining the upper portion completely filled with liquid, means for maintaining the lower portion filled with liquid to a predetermined level, said suction line includ-ing a first portion returning from said motor discharging into said upper portion of said liquid container, a conduit extending from a location adjacent the top of said upper container to a location intermediate the height of said lower portion of said containery andvterm-inating in a `discharge opening of reduced dimension submerged in the liquid in said lower portion of said container, and a second portion of said suction line including an opening submerged in the liquid of said lower portion in alignment with but spaced in an axial direction away from the discharge opening of said conduit in the direction of discharge flow, said conduit extending back to said pump means, whereby liquid returning from said motor is directed tirst into the upper portion of said container where it is forced to iiow upwardly in said upper portion and then downwardly through said conduit into the liquid of the lower portion of said container and thence into the second portion of said suction line.

`References Cited in the tile of this patent Y UNITED STATES PATENTS 2,251,664 Davis Aug. 5, 1941 2,571,932 Olsson Oct.' 16, 1951 2,753,011 Downs Jury 3, 1956 2,757,582 Freeman et al. Aug. 7, 1956 V2,765,867 Revallier et al. Oct. 9, 1956 2,789,655 Michael et al. Apr. 23,1957 2,811,218 Winslow Oct. 29, 1957 A l f3,... 

